The present invention relates to a vertical pipe expander.
Machines of this type are used to expand pipes assembled with the fins of finned heat exchangers.
Heat exchangers, after the initial assembly step in which individual fins are fitted on pipes so as to form a finned pack, require this additional technological operation in order to obtain stable contact between the fins and the very pipes.
This contact allows optimum heat transmission between the fluid that flows inside the pipes, and the fluid, normally air, that strikes the fins.
A vertical pipe expander is conceptually a hydraulic press with various electromechanical servomechanisms, in which a finned heat exchanger is arranged vertically in a downward region on a supporting frame.
In the region above the supporting frame there are rods provided at their tips with pipe expanding cones; such rods are associated with a corresponding support for vertical movement and are arranged vertically.
The rods that support the pipe expanding cones are actuated simultaneously so as to advance downward, entering the pipes of the heat exchanger so as to widen their diameter by means of the cones.
However, pipe expanders of the known type are not free from drawbacks.
They are in fact particularly inflexible from the point of view of operation.
Heat exchangers can be manufactured with pipes having different thicknesses and diameters.
This entails the use of cones that are specific for each pipe thickness, therefore entailing the need to replace the rods when the type of exchanger varies.
Furthermore, since the arrangement of the pipes varies for each exchanger type, it is necessary to provide a device for selecting the cone supporting rods that must perform the expansion whenever it is necessary to an exchanger whose configuration is different from that of a preceding one.
The rod replacement operation is currently completely manual; furthermore, since the cones have size differences that are difficult to distinguish with the naked eye, the machine can often be subjected to an incorrect setting.
Machine downtimes are therefore particularly high, since the setting operation also is completely manual.
The aim of the present invention is to solve or substantially reduce the problems of known types of vertical pipe expander.
Within this aim, an important object is to provide a pipe expander that is operatively flexible and versatile.
Another object is to provide a machine in which cone supporting rods of different sizes can be changed completely automatically.
Another object is to provide a pipe expander with automatic selection of the rods to be used in the technological operation.
Another object is to provide a pipe expander that requires very short machine downtimes and setup times.
Another object is to provide a machine that is safe for the user and ergonomic.
This aim and these and other objects that will become better apparent hereinafter are achieved by a pipe expander of the vertically elongated type that comprises, on a supporting frame, supporting means for rods that support pipe expanding cones, which can perform a vertical translational motion and are arranged above a seat for a heat exchanger to be subjected to pipe expansion, characterized in that it comprises at least one cone supporting rod magazine that is arranged vertically so that the cones are directed downwardly, to be arranged, during a machine setup step, at said seat, said supporting means for cone supporting rods being constituted by a device for engaging and supporting rods at their rear end portion, said rod engagement and support device being associated with a device for selecting the rods of the magazine to be engaged or released, with said magazine arranged in said seat.